The present invention relates to games or sports balls and, more particularly, to game or sport balls with an inflatable bladder. More specifically, although not solely limiting thereto, this invention relates to games or sports balls having a cloth, or more generally, woven material, wrapped inflatable bladder. This invention also relates to methods of making game or sport balls and an inflatable bladder therefor.
Many sports or games balls include an inner body of an inflatable bladder and an outer body enclosing the bladder. The outer body is generally made up of an assembly of flexible panels which are usually made, for example, of leather, synthetic leather such as polyurethane (PU) or polyvinyl chloride (PVC) or other durable materials. The panels are generally joined together by hand or machine sewing or by adhering them onto the bladder carcass according to standard or conventional shapes and patterns.
For example, a conventional basketball comprises eight leaf-shaped panels which are affixed onto a bladder carcass having a plurality of protruding ribs which together define the perimeters of the leaf-shaped panels. For a conventional soccer ball, the outer body is made of an assembly of panels comprising twelve pentagonal panels and twenty hexagonal panels by edge-to-edge sewing. The outer body of a conventional volleyball consists of eighteen rectangular panels assembled by edge-to-edge sewing.
In general, the outer body of a sports or games ball provides a definitive size, pattern, shape and configuration characterizing the type of sport the ball is primarily designed for. On the other hand, it is also the function of the outer body to provide permanence of shape and to maintain the overall shape and dimensions when the ball is subject to a range of inflation pressures. In addition, the rigidity and durability of a conventional sports ball may primarily depend on the outer body. Thus, the outer body must be designed and made to withstand and absorb all the impact forces which can be expected during the normal course of the sport for which the ball is designed.
The inner body of a conventional sports ball generally includes an inflatable bladder which usually has a valve stem for air inflation and deflation. In general, when air is pumped into the inflatable bladder, the pressurized air inflates the bladder which in turn causes the outer body to expand and attain an overall shape as defined by the design and structure of the outer body.
At the same time, the tension on the outer body due to inflation of the inner body gives the sports ball the necessary bouncing characteristics. Hence, it is generally understood that the structural integrity of a conventional sports ball depends largely, if not solely, on the outer body rather than the inner inflatable bladder. As a result, the quality and strength of the constituting outer panels as well as their sewing and the sewing linings is generally regarded as directly affecting the quality and durability of a sports ball.
To withstand high and repetitive impact forces and to provide high durability, the outer bodies are usually made of thick and, usually cushioned, panels. This makes even sewing or stitching more difficult and stringent quality control is required. As a result, yielding will be low with a high reject rate. In addition, parts of the stitching or sewing may be damaged as a result of repeated localized hitting on a ball. As a result, localized weakness may appear on the outer body. When the sports ball is inflated or over-inflated, the pressurized air will be most apparent at such weak points and may cause adverse deformation of the overall shape of the ball. Such deformation may result in un-predictable bouncing orientation or characteristics of the ball when hit or may even cause the ball to burst at or through the weaker portions when subject to heavy impact.
In order to relieve the outer body from bearing the sole responsibility of fulfilling all he afore-mentioned functions of a conventional outer body of a sports ball, there have been proposals to employ a re-inforced inflatable bladder within the outer body of a game ball instead of the conventional bladder which is made from a single layer of thin rubber sheet. A natural consequence of the use of such an re-inforced bladder is that a less stringent quality demand can be placed on the design and making of the outer body, thereby also reducing manufacturing rejects and costs in favour of consumers.
For example, in U.S. Pat. No. 2,789,821, there is disclosed a sports ball having an inflatable bladder which is wrapped within a winding of synthetic cord or thread. In that construction, an inflated bladder is firstly applied with fabric tapes which are applied circumferentially on orthogonal planes on the surface of an inflated bladder and passing through the valve stem in order to limit the expansion of the bladder in the two planes of the circles. The taped bladder is then covered with a winding of threads for re-inforcement.
In U.S. Pat. No. 5,772,545 and U.S. Pat. No. 6,220,979, there are disclosed sports balls having a wound-core covered with windings of thread, such as nylon yarn, in order to enhance durability and to resist enlargement of the game ball over time.
However, re-inforcing a soft-bladder by thread-winding is a tedious process which requires a large length of thread as well as a large number of windings. In addition, such thread-wound inflatable bladders tend to be more rigid and less user-friendly. Also, a thread-wound inflatable bladder is usually very light and additional weight must be added to the outer body in order to attain the necessary overall weight in order to meet product standards or specifications. This will add to costs and is therefore less attractive. Furthermore, when thread winding is applied on the bladder, it will usually follow the bladder""s original unwound shape and size. If the shape and/or size of the original unwound bladder is not correct, the wound bladder will remain permanently in its incorrect size and shape.
Hence, it will be highly advantageous if there can be provided relatively simple and inexpensive methods for making games or sports balls with a re-inforced inflatable bladder while alleviating the shortcomings associated with the thread-wound bladders. In other words, it will be highly desirable if the known benefits of a re-inforced inflatable bladder can be attained by forming a reinforced bladder using a relatively simple and inexpensive method. In one respect, it will be highly advantageous if the improved method for making an re-inforced bladder can be utilized to form an inflatable bladder having a size which is substantially restricted by the reinforcement when inflated with a range of air pressure which can be expected from an ordinary pumping device for sports balls. At the same time, it will also be of great general advantage if such bladders will maintain a reasonable and even degree of flexibility in most orientations of the bladder and also retains the expected bouncing characteristic of an inflatable bladder.
Hence, it is an object of the present invention to provide methods for making game balls and re-inforced inflatable bladders for game balls in which the inflatable bladders are re-inforced by relatively simple means and methods so that a durable inflatable bladder can be obtained without compromising the beneficial characteristics of an inflatable bladder.
In one aspect, such an re-inforced inflatable bladder would have a size and shape which is substantially restrained by the re-inforcement when subject to an expected range of pumping air pressure while at the same time maintaining a high and even degree of flexibility.
It is another object of the present invention to provide a substantial re-inforced inflatable bladder wherein the weight of the bladder can be relatively easily adjusted by the choice of the re-inforcing materials in order to meet the general weight requirements while substantially retaining the bouncing characteristics of conventional sports balls. As a minimum, it is an object of the present invention to provide the public with a choice of sports balls having an improved type of re-inforced inflatable bladder and methods of making the same.
In general, it is an object of the present invention to provide an improved inflatable bladder for sports- or games-balls having an outer body formed generally with a plurality of panels sewn together in which the enhanced characteristics of the inflatable bladder lessens the demand of quality are robustness on the outer body.
According to the present invention, there is provided a method of making a sports- or games-ball having an inflatable bladder including the steps of:
inflating said bladder until the surface of said bladder is generally under tension,
adhering a plurality of woven material pieces to the outer surface of said inflated bladder,
moistening said woven material wrapped inflated bladder,
placing said woven material wrapped and inflated bladder inside a mould,
further inflating said woven material wrapped bladder to a pre-determined pressure until said bladder presses against said mould,
apply heat to said woven material wrapped and inflated bladder inside said mould to strengthen the bonding between said bladder and said cloth pieces.
According to another aspect of the present invention, there is provided a method of making an inflatable bladder of a ball by applying a plurality of cloth- or woven-material patch pairs onto the surface of said inflatable bladder, where at least some of said pairs of patches are disposed in a diametrically opposite manner on the surface of said bladder.
According to yet another aspect of the present invention, there is provided a ball having a hollow inflatable bladder, wherein said bladder includes a plurality of cross-shaped cloth pieces disposed substantially at the diametrically opposite ends of said bladder and said bladder is enclosed within an outer body made from a plurality of panels sewn together.
According to a fourth aspect of the present invention, there is provided a ball having a hollow inflatable bladder, wherein said bladder further includes a plurality of overlapping cross-shaped cloth pieces disposed on the surface of said bladder.
Preferably, the woven material-wrapped and bonded bladder is made into the shape of said mould.
Preferably, at least some of said plurality of woven-material pieces are adhered in pairs of pieces on orthogonal planes.
Preferably, the said method further including the steps of deflating said bladder and, removing said bladder from said mould.
Preferably, at least some of said woven-material pieces are pre-treated with a water-soluble adhesive before adhering to said inflatable bladder.
Preferably, at least some portion of said woven-material pieces overlap with adjacent woven-material pieces, the woven material is a cloth material woven from synthetic yarn.
More preferably said synthetic yarn comprises fibre-glass or polyester yarn.
Preferably, the plurality of woven-material pieces are adhered to said inflatable bladder in the following manner:
forming a first woven-material patch at one pole of said inflated bladder and surrounding the air-inlet valve of said bladder, wherein said pole coincides with the location of said valve,
forming a second woven-material patch at the opposite pole of said inflated bladder, wherein said opposite pole is located diametrically opposite said valve,
joining said first and second woven-material patches by a plurality of longitudinally extending cloth pieces to form a first and a second circumferential of woven-material wrapping on said inflated bladder,
adhering a plurality of latitudinal running cloth pieces along the equator of said inflated bladder until the equator of said inflated bladder until the equator of said inflated bladder is substantially covered by woven material,
applying further cloth pieces until the exposed portion of said inflated bladder is substantially covered by woven-material pieces.
Preferably, the woven-material patches surrounding said poles forms a cross or square shape.
Preferably, the longitudinally extending woven material pieces join said first and second polar patches by connecting the corresponding salient part of said polar patches.
Preferably, the first and second polar of patches are joined by at least four latitudinal running woven material pieces.
Preferably, the bladder includes a plurality of cloth- or woven- material patch pairs bonded onto the surface of said inflatable bladder, wherein at least some of said pairs of patches are disposed in a diametrically opposite manner on the surface of said bladder.
Preferably, the bladder is enclosed within an outer body made of a plurality of sewn panels.
Preferably, the inflatable bladder includes a plurality of cross-shaped cloth pieces pairs disposed substantially at the diametrically opposite ends of said bladder.
Preferably, the inflatable bladder is substantially covered by a plurality of woven material patches with overlapping of adjacent patches.